(11) EP 0 284 347 A3


(88) Date of publication A3:
12.07.1989 Bulletin 1989/28

(43) Date of publication A2:
28.09.1988 Bulletin 1988/39

(21) Application number: 88302503.3

(22) Date of filing: 22.03.1988
(51) International Patent Classification (IPC)4G01M 3/36, G01M 3/38
(84) Designated Contracting States:

(30) Priority: 27.03.1987 JP 44292/87
10.08.1987 JP 121444/87

(71) Applicant: Toyo Glass Company Limited
Tokyo (JP)

(72) Inventors:
  • Yamato, Yoshihiro
    Yokohama-shi Kanagawa-ken (JP)
  • Gomibuchi, Tadashi
    Chiyoda-ku Tokyo (JP)

(74) Representative: Dixon, Donald Cossar et al
Gee & Co. Chancery House Chancery Lane
London WC2A 1QU
London WC2A 1QU (GB)

(56) References cited: : 

    (54) A device for inspecting the degree of vacuum in a sealed vessel

    (57) A device for inspecting the degree of vacuum in a sealed vessel is disclosed in which a high degree of accuracy is not required for positioning of an object vessel (14) and in which the degree of vacuum of an object vessel (14) can be detected with a high S/N ratio under a reduced influence of fluctuations in size or configuration of a top (lid) wall (15a) of an object vessel (14). The device comprises a large diameter lens (4) for refracting rays of light from a light source (2) into rays of light to be irradiated upon an area including a lid wall (15a) of a sealed vessel (14) held at a predetermined inspection position, a beam splitter (5) for passing part of rays from the large diameter lens (4) therethrough and for reflecting reflected rays (13a) from the lid wall (15a) of the sealed vessel (14), a condenser lens (6) for condensing reflected rays from the beam splitter (5), an image sensor (7) for detecting the thus condensed rays, and a comparator circuit (21) for comparing an output voltage of the image sensor (7) with a reference voltage to develop a signal representing whether the sealed vessel (14) is acceptable or is to be rejected.

    Search report